1. Field of the Invention
The present invention is generally in the field of semiconductor dies and circuits. More particularly, the invention is in the field of power management in semiconductor dies.
2. Background Art
Semiconductor device leakage current (e.g. transistor leakage current) can cause an undesirable increase in power consumption in semiconductor dies utilized in electronic devices such as battery powered devices, which include wireless communication devices, such as cell phones, and wireless human interface devices, such as wireless keyboards, mice, and game controllers. In an effort to reduce leakage current, a power management technique can be utilized whereby a power island of a semiconductor die is used to turn on the remaining regions of the die, and to turn off those remaining regions whenever the battery powered device is idle.
A conventional power island, which remains continuously activated (i.e. remains continuously powered on) in the idle mode of operation, can include a detection circuitry for detecting an external event, such as a depressed key on a wireless keyboard or a mouse movement, and a processing circuitry for event verification. The conventional power island is situated in a thick oxide region of the die, which includes semiconductor devices with thick gate oxide, and is utilized to turn on (or turn off) thin oxide regions of the die, which include semiconductor devices with thin gate oxide. Semiconductor devices in the thick oxide region of the die can have a higher threshold voltage than semiconductor devices in the thin oxide region, which reduces leakage current in the thick oxide region, i.e. the power island region of the die, that remains powered on during idle mode of operation.
However, as a result of the thick gate oxide, semiconductor devices in the thick oxide region of the die can have a significantly larger size than semiconductor devices in the thin oxide region. Thus, although the conventional power island reduces semiconductor device leakage, it (i.e. the conventional power island) also consumes a large area of the die, which can be particularly undesirable as devices are scaled down in advanced technologies.